include/asm-m68k/semaphore.h

   1 #ifndef _M68K_SEMAPHORE_H
   2 #define _M68K_SEMAPHORE_H
   3
   4 #define RW_LOCK_BIAS             0x01000000
   5
   6 #ifndef __ASSEMBLY__
   7
   8 #include <linux/linkage.h>
   9 #include <linux/wait.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/rwsem.h>
  12 #include <linux/stringify.h>
  13
  14 #include <asm/system.h>
  15 #include <asm/atomic.h>
  16
  17 /*
  18  * Interrupt-safe semaphores..
  19  *
  20  * (C) Copyright 1996 Linus Torvalds
  21  *
  22  * m68k version by Andreas Schwab
  23  */
  24
  25
  26 struct semaphore {
  27         atomic_t count;
  28         atomic_t waking;
  29         wait_queue_head_t wait;
  30 };
  31
  32 #define __SEMAPHORE_INITIALIZER(name, n)                                \
  33 {                                                                       \
  34         .count          = ATOMIC_INIT(n),                               \
  35         .waking         = ATOMIC_INIT(0),                               \
  36         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)    \
  37 }
  38
  39 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
  40         struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
  41
  42 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
  43
  44 static inline void sema_init(struct semaphore *sem, int val)
  45 {
  46         *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
  47 }
  48
  49 static inline void init_MUTEX (struct semaphore *sem)
  50 {
  51         sema_init(sem, 1);
  52 }
  53
  54 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
  55 {
  56         sema_init(sem, 0);
  57 }
  58
  59 asmlinkage void __down_failed(void /* special register calling convention */);
  60 asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  61 asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  62 asmlinkage void __up_wakeup(void /* special register calling convention */);
  63
  64 asmlinkage void __down(struct semaphore * sem);
  65 asmlinkage int  __down_interruptible(struct semaphore * sem);
  66 asmlinkage int  __down_trylock(struct semaphore * sem);
  67 asmlinkage void __up(struct semaphore * sem);
  68
  69 /*
  70  * This is ugly, but we want the default case to fall through.
  71  * "down_failed" is a special asm handler that calls the C
  72  * routine that actually waits. See arch/m68k/lib/semaphore.S
  73  */
  74 static inline void down(struct semaphore *sem)
  75 {
  76         register struct semaphore *sem1 __asm__ ("%a1") = sem;
  77
  78         might_sleep();
  79         __asm__ __volatile__(
  80                 "| atomic down operation\n\t"
  81                 "subql #1,%0@\n\t"
  82                 "jmi 2f\n\t"
  83                 "1:\n"
  84                 LOCK_SECTION_START(".even\n\t")
  85                 "2:\tpea 1b\n\t"
  86                 "jbra __down_failed\n"
  87                 LOCK_SECTION_END
  88                 : /* no outputs */
  89                 : "a" (sem1)
  90                 : "memory");
  91 }
  92
  93 static inline int down_interruptible(struct semaphore *sem)
  94 {
  95         register struct semaphore *sem1 __asm__ ("%a1") = sem;
  96         register int result __asm__ ("%d0");
  97
  98         might_sleep();
  99         __asm__ __volatile__(
 100                 "| atomic interruptible down operation\n\t"
 101                 "subql #1,%1@\n\t"
 102                 "jmi 2f\n\t"
 103                 "clrl %0\n"
 104                 "1:\n"
 105                 LOCK_SECTION_START(".even\n\t")
 106                 "2:\tpea 1b\n\t"
 107                 "jbra __down_failed_interruptible\n"
 108                 LOCK_SECTION_END
 109                 : "=d" (result)
 110                 : "a" (sem1)
 111                 : "memory");
 112         return result;
 113 }
 114
 115 static inline int down_trylock(struct semaphore *sem)
 116 {
 117         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 118         register int result __asm__ ("%d0");
 119
 120         __asm__ __volatile__(
 121                 "| atomic down trylock operation\n\t"
 122                 "subql #1,%1@\n\t"
 123                 "jmi 2f\n\t"
 124                 "clrl %0\n"
 125                 "1:\n"
 126                 LOCK_SECTION_START(".even\n\t")
 127                 "2:\tpea 1b\n\t"
 128                 "jbra __down_failed_trylock\n"
 129                 LOCK_SECTION_END
 130                 : "=d" (result)
 131                 : "a" (sem1)
 132                 : "memory");
 133         return result;
 134 }
 135
 136 /*
 137  * Note! This is subtle. We jump to wake people up only if
 138  * the semaphore was negative (== somebody was waiting on it).
 139  * The default case (no contention) will result in NO
 140  * jumps for both down() and up().
 141  */
 142 static inline void up(struct semaphore *sem)
 143 {
 144         register struct semaphore *sem1 __asm__ ("%a1") = sem;
 145
 146         __asm__ __volatile__(
 147                 "| atomic up operation\n\t"
 148                 "addql #1,%0@\n\t"
 149                 "jle 2f\n"
 150                 "1:\n"
 151                 LOCK_SECTION_START(".even\n\t")
 152                 "2:\t"
 153                 "pea 1b\n\t"
 154                 "jbra __up_wakeup\n"
 155                 LOCK_SECTION_END
 156                 : /* no outputs */
 157                 : "a" (sem1)
 158                 : "memory");
 159 }
 160
 161 #endif /* __ASSEMBLY__ */
 162
 163 #endif